Maleamic acids, such as hydroxyphenyl maleamic acid, are disclosed in U.S. Pat. No. 4,433,114 as an additive for use in sulfur vulcanized rubber. In addition N-(4-hydroxyphenyl)maleimide is a known rubber additive as taught in JA 60-163831. These additives are known to improve tack, green strength and/or non-black filler interaction in a diene rubber. Conventionally, N-(4-hydroxyphenyl)maleimide is prepared by reacting aminophenol and maleic anhydride in the presence of large amounts of a highly polar organic solvent, e.g., acetone. After the reaction has proceeded at room temperature for approximately 2 hours, the reaction mixture is heated to 50.degree. C. for an additional 4 hours and then cooled. Acetic anhydride and sodium acetate are then added to the solution and stirred while heating to 50.degree. to 60.degree. for 6 hours. Upon completion of the reaction, the mixture is cooled and water is added to coagulate the product. After filtration and washing with water, the product is dried. Unfortunately, this method is characterized by use of very expensive polar solvents which must then be recovered. With the increase in interest associated with the use of maleimide compounds in rubber, new and more economical methods for their preparation are needed.